(a) Field of the Invention
The present invention relates generally to a balancing valve assembly of a cold and hot water mixing valve, and more particularly to an improved structure in which a cold and hot water control unit is connected to a water pressure balancing valve as an integral whole.
(b) Description of the Prior Art
A conventional water faucet achieves mixing of hot and cold water and flow regulation by utilizing a mixing valve. The mixing valve has two tightly overlapping ceramic disks in which the lower one is fixed while the upper one is movable on the lower disk by means of a control lever. The fixed disk is provided with two inlet openings respectively connected to two divided hot and cold water inlets and an outlet opening for conducting water to the mouth of the faucet. The movable disk is provided with a mixing space where hot and cold water can mix and may selectively connect any one or both of the inlet openings of the fixed disk to the outlet opening.
In use, the conventional mixing valve is directly connected to the water piping. Therefore, when supply of either hot water or cold water is unstable, the water coming out of the faucet will be suddenly cold and suddenly hot. In particular, if the supply of cold water is drastically reduced or even stopped and the supply of hot water is continued, the water coming out of the faucet will be very hot, which may scald the user seriously. In order to correct this defect, the hot and cold water pipes are firstly connected to a balancing valve before they are connected to the mixing valve so that when water pressure in the hot or cold water pipe suddenly changes, the balancing valve will automatically cut off both cold water and hot water supply to ensure safety.
With reference to FIGS. 12 and 13, a balancing valve device generally includes a valve seat 1' and a valve body 2'. The valve seat 1 is internally provided with a chamber 11' provided with cold and hot water inlets 12', 13' and outlets 14', 15'. As shown in FIG. 15, the valve body 2' generally includes a cylindrical sleeve 21' and a stop 22'. The stop 22' is precision-fitted inside the sleeve 21' such that it may freely slide. In addition, the sleeve 21' and the stop 22' are respectively and symmetrically provided with two water holes 211', 212', 221' and 222', with a partition 223' disposed between water holes 221' and 222'. The balancing valve 2' is installed in the chamber 11', and the partition 223' divides the chamber 11' into a cold water flow space and a hot water flow space so that water flowing in from the water inlets 12' and 13' past the water holes 211', 212', 221' and 222' and out through the water outlets 14' and 15'. During the passage of water through the balancing valve device, two end surfaces of the partition 223' of the stop 22' are respectively subjected to water pressure inside the cold and hot water flow spaces. Therefore, when water pressure in the hot or water pipe changes, the partition will be subjected to the action of the side with the greater water pressure so that the entire stop 22' displaces towards the side with the lesser water pressure, resulting in closure of the water holes 211', 212', 221' and 222' and stopping of the flow of hot and cold water (as shown in FIG. 14).
In the past, such balancing valve is independently and externally installed on the hot and cold water pipes before they connect to the water faucet. This is not only unsightly but also makes piping design and pipe laying difficult. Installation and operation thereof are also inconvenient. Although there are efforts to overcome these drawbacks by simplifying the structure, or combining the balancing valve with the mixing valve as shown in FIG. 15. The balancing valve is shown to be reduced and directly provided below the mixing valve to form a structure including a mixing valve casing 3', an upper bottom plate 4' and a lower bottom plate 5'. The casing 3' has installed therein, in sequence, a control lever device 31', a movable disk 32', and a fixed disk 33', a seal 41' fitted to a top side of the upper bottom plate 4' with its lugs 42' fastened to corresponding fastening holes 35' at the bottom side of the casing 3'. In addition, the upper bottom plate 4' is provided with through cold and hot water holes 43' and mixed water hole 44' respectively communicating with cold and hot water holes 331' and mixed water hole 332' of the fixed disk. Besides, a balancing valve upper chamber 45' is provided below the cold and hot water holes 43' of the upper bottom plate 4'. Furthermore, a seal 51' is fitted on a top side of the lower bottom plate 5' which is secured to the bottom side of the upper bottom plate 4' using screws 52'. In addition, the lower bottom plate 5' is likewise provided with through cold and hot water holes 53' and mixed water hole 54' respectively communicating with the cold and hot water holes 43' and mixed water hole 44' of the upper bottom plate. A balancing valve lower chamber 55' is provided above the cold and hot water holes 53' of the lower bottom plate 5' such that the lower chamber 55', together with the upper chamber 45', may sealingly enclose a balancing valve 2' therebetween. After assembly, water from the water pipes flow past the through holes 54' of the lower bottom plate into the communicating spaces divided by the balancing valve 2' and through the through holes 43' of the upper bottom plate to the water holes 331 of the fixed disk and into a mixing chamber 321 of the movable disk. When the mixing chamber 321' and the water holes 332' ofthe fixed disk are connected, the mixed water flows via the water holes 332' and through holes 44' and 54' into the faucet cavity and out through the faucet opening for use.
Although the above-described structure combining the balancing valve and the mixing valve has solved the problem of unsightliness and the difficulties in piping, installation and operation, it has other problems. For instance, as this structure is comprised of a number of components, the latter must have relatively high precision in order that tightness of the structure after assembly is ensured. And in order to ensure tightness, washers or seals have to be provided between the necessary components, which means difficult and inconvenient assembly. Besides, if any of the components is not properly aligned, it will affect the tightness of the structure. Additionally, since the components are connected by fastening means or screws, it is difficult to ensure that the connections are secure. If any of the connections is loosened, the tightness of the structure will be seriously affected as well. Improvement is therefore necessary.